I took out my 335is to the track this weekend - and was extremely happy out the temp levels. I was running with another 335 -- which went into limp mode and lost power on all of the later in the morning (e.g. hotter) sessions.
We compared temps - and consistently the 335is was running at least 10f or more degrees cooler. I used to have one of the early 335 e92s - and the 335is definitely seems more at home on the track. From my view of the world BMW did a pretty good job with the extra radiator, duct work, etc. on the IS.